As we all know, an air-conditioning cooling tower, in particular to an industrial air-conditioning cooling tower, retains sufficiently abundant energy for cooling circulating water during the design, in order to realize the energy-saving purpose, a water turbine is used for recovering the part of the abundant energy and transforming the abundant energy to rotation mechanical energy of the water turbine for driving a cooling fan, thereby eliminating a traditional high-power cooling motor and realizing very significant energy-saving effect.
Presently, a circulating water abundant water head of the industrial air-conditioning cooling tower in China is 4 m-15 m, and the pressure water head of 0.5 m-1 m is required in the position for distributing water pipes, so that the water turbine for recovering the part of the circulating water abundant water head works in an environment with back pressure; but the rotational speed of the fan of the cooing tower is lower, in order to realize direct connection with the fan of the cooling tower, the low-speed mixed flow type water turbine must be selected; however, in the current spectrum of the water turbines in China, the low-speed mixed flow type water turbine which can meet the working environment and be directly connected with the cooling fan is still absent, the driving mode of connecting the ordinary mixed flow type water turbine with the fan of the cooling tower through a speed reducer needs to be adopted, as the working conditions of a speed reduction box are poorer, not only the noise is great and the service life is short, but also the manufacturing cost is correspondingly improved. Therefore, the mixed flow type water turbine which can meet the low unit rotational speed under the working environment and be directly connected with the fan of the cooling tower is developed, thereby having great practical significance.
An applicant thinks that the output rotational speed of the water turbine can be controlled within the desired range by reasonably designing sizes of all parts of the water turbine through a lot of calculation, analysis and experiments.